1. Field of the Invention
This invention relates to an image processing system and more particularly to an image processing system which is arranged to correct the aberration of a photo-taking optical system in an image recording/reproduction system or a transmission system.
2. Description of the Related Art
The photo-taking optical system of a video camera or the like is designed to minimize the aberration thereof. Despite the design, however, it is inevitable to have some degree of aberration remaining. A method for digitally correcting the residual aberration has been disclosed in an article entitled xe2x80x9cReal Time Correction of Deviation of Dynamic Registration caused by Lensxe2x80x9d and appeared in the xe2x80x9cTechnical Reportsxe2x80x9d, TEBS 96-4, 1984, of the Television Society.
In accordance with the above-stated prior art method, optical information such as the focal length, the focusing state, the aperture value, etc. of the photo-taking lens is read out from a lens barrel part and an aberration taking place in the photo-taking state of the lens is computed (or an aberration value which has been computed and stored in a memory is read out); and the aberration is corrected by controlling mainly the scanning position of a camera tube.
The term xe2x80x9caberrationxe2x80x9d as used herein includes an image distortion which is shown in FIG. 6(a) of accompanying drawings; a lateral chromatic aberration shown in FIG. 6(b); parallel color deviation shown in FIG. 6(c); and a shading as shown in FIG. 6(d). The aberrations shown in FIGS. 6(a), 6(b) and 6(d) result from the optical factors of the photo-taking lens and depend on the state of the lens. The aberration shown in FIG. 6(c), on the other hand, either results from an error in mounting position of the camera tube, a solid-state image sensor or the like or results from rattling, slanting and decentering which take place while the lens is moved.
The aberration correcting method mentioned above is intended to obtain an aberration-corrected signal when it is output from the camera tube and is thus applicable only to the camera tube. It is not applicable to a solid-state image sensor, because: In the case of the solid-state image sensor, many photo-electric conversion elements are fixedly arranged in a matrix-like state. Their positions are thus invariable. Further, the use of the camera tube is undesirable because of its large size, a high cost and a short life. It is, therefore, impractical to use camera tubes and, hence, the above-stated method for general consumer appliances.
It is conceivable to solve the above-stated problem by temporarily storing image information output from a solid-state image sensor in an image storage device which is composed of a semiconductor memory and by subjecting it to an aberration correcting process. However, the image storage device must be arranged to permit random access. Then, a large address circuit is necessary for random access. In addition to that, the method necessitates use of a large, high-speed computing circuit in carrying out address computation for aberration correction. This increases the size and weight of the camera.
It is, therefore, an object of this invention to provide an image processing system which is capable of giving a substantially aberration-corrected image signal without causing the inconveniences mentioned above.
The image processing system according to this invention is characterized in that: In a system for transmitting a video signal obtained by a camera to a recording/reproducing device or to a discrete device via a transmission line, the camera is provided with generation means for generating a photo-taking state signal which is arranged to indicate the aberration. In combination with this, the video signal reproducing or receiving device is provided with correction means for correcting and adjusting the aberration of the video signal according to the photo-taking state signal received.
The above-stated generation means enables the video signal reproducing or receiving device to know information on the aberration or a camera shake taking place in shooting. The video signal thus can be corrected by the correcting means according to such information. The correcting action does not require the camera itself to have any large special circuit. Therefore, the camera can be arranged to be compact in size and light in weight. Since the condition of each individual shot is detectable, the correction can be appositely accomplished according to the condition. A picture thus can be obtained in high quality. Further, since the shooting condition is not to be detected from the video signal, the correcting means can be arranged in a relatively simple manner.
The above and further objects and features of the invention will become apparent from the following detailed description of embodiments thereof taken in connection with the accompanying drawings.